Since 1990s,with the active attention to underbal anced drilling (UBD),this technology has developed rapidly.Therefore,the applica tion of coiled tubing (CT) in UBD has been improved.

• 90年代以来，欠平衡钻井受到人们高度重视，欠平衡钻井技术迅速发展，钻井数逐年增加，从而也促进了连续油管在欠平衡钻井中的应用。